1. Ergonomic Design
This is the most important factor that must be fulfilled because you'll use your keyboard every day.

Ergonomic keyboard isn’t going to cause you any strain.

Mostly they come with adjustable height and tilt so you can set the keyboard at the right level for where you’re sitting.

Pro tip: a wrist rest will be a great addition, if you crave for more comfort.

2. Wired or Wireless
• Wired keyboard - do not offer portability, but they are cheaper and do not require batteries. Perfect choice, if you think your keyboard will stays in one place most of the time.

• Wireless keyboard – offer great portability because there are no annoying cables, but they are more expensive and require batteries. Perfect choice if you think you will use it in various positions. [1]

If you plan to buy a wireless keyboard make sure you also check the range. Some wireless keyboards can operate through walls, while others need to be in the same room as your workstation in order to operate. [2]

3. Switches
• Silicone dome switches - makes for a soft, mushy feel as you press each key. However, because of repeated flexing of the rubber membrane causes it to break down, lose their springiness and responsiveness over time.

• Scissor switches - have a shallow typing feel, but are generally more durable than rubber dome switches alone.

• Mechanical switches - a bit more intricate, with a spring loaded sliding keypost under every key.

There are several variations available, each tweaked to provide a slightly different feel or sound, but generally, mechanical switches provide better tactile feedback and have more of the "clickety-clack" sound that many associate with typing.

The sturdy switch mechanisms and long-lasting springs are significantly longer lasting, and more easily reparable. These switches also register each keystroke with a much shorter amount of travel, making them ideal for touch typists. [3]

4. Other Features To Consider:
• Illuminated keys for typing at low light conditions.
• Basic media features such as playback controls and volume up and down.
• Anti-ghosting to allow multiple keystrokes to be registered simultaneously.
• Extra keys for Macro commands, letting you pre-arrange complex strings of commands and activate them with a single press of a button.

5. What Other Users Have Said
There are great advantage if you buy your computer keyboard online is that you can see directly the opinions of other users.

And that is why large and trusted online retailer like Amazon.com displaying their customer reviews including the star rating. It will give you a real picture of a product you plan to buy.

The more the number of buyer reviews and the higher the star rating, the better the product in the eyes of consumers.

For your information, people who can submit a product review on Amazon.com must make the purchase first. So rest assured, you will get an honest review from them.